Coated abrasive cones

ABSTRACT

A flexible abrasive tool having a conical shape is provided with tear means whereby the tool can be separated, if desired, into two or more abrasive tools of the same conical shape but of lesser desired vertical height.

United States Patent Christian 1 June 20, 1972 COATED ABRASIVE CONES[72] Inventor: Warren E. Christian, Troy, N.Y.

[73] Assignee: Norton Company, Troy, N.Y.

[22] Filed: March 8, 1971 21 Appl. No.: 121,918

52 user ..s1/394,51 3s0 s1 lnLCl. ..B24d 17/00, B24d11/00 5sFieldofSearch ..5l/394,358,407,380,381,

51/384, 397, 407; 229/21, 51 DB; 206/56 R References Cited UNITED STATESPATENTS 2,150,207 3/1939 Currie ..206/56 R 3,110,137 11/1963 Gross..5l/380 Primary Examiner-Othell M, Simpson Attorney-Hugh E. Smith andHerbert I... Gatewood [57] ABSTRACT A flexible abrasive tool having aconical shape is provided with tear means whereby the tool can beseparated, if desired, into two or more abrasive tools of the sameconical shape but of lesser desired vertical height.

7 Claims, 3 Drawing Figures COATED ABRASIVE CONES BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates tocoated abrasive tools employed in the polishing, cutting, and finishingof various materials.

2. Description of the Prior Art In many instances one finds it necessaryto grind conical shaped openings or structures such as those found,particularly, in internal combustion engines. Over the years abrasivearticles in the shape of a frustum or truncated cone have been foundsatisfactory for this purpose. One disadvantage, however, with the useof these abrasive articles is that, in general, a relatively largesupply of various sizes must be kept on hand. This is so even where thesurfaces being ground are of the same conical shape because the surfacesmay not be of the same depth. Thus extra storage facilities must beprovided by the user of such abrasive articles and it is necessary, insome cases, that large users maintain extra inventory records as well asextra records for ordering and reordering of the abrasive supplies.

SUMMARY OF THE INVENTION In accordance with my invention, a cone shapedabrasive article is provided with tear means whereby the article may, ifdesired, be separated by the user into two or more abrasive articles ofthe same conical shape but of a lesser desired vertical height.

With my invention the disadvantages above pointed out may be avoided.Moreover, most advantageously, the manufacturer of such an abrasivearticle can manufacture, at one time, a conical shaped abrasive toolwhich is suitable for more than one grinding application. Two or moresizes of a coneshaped abrasive tool can thus be provided in onerelatively simple, easy, operation requiring no additional processingsteps over that presently existing in the manufacturing operation.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understoodby referring to the drawing, as one reads the specification, in whichlike numerals refer to like parts in the various views, and in which:

FIG. 1 is a top plan view of an arcuate section of coated abrasivematerial which is to be formed into a coated abrasive frustum ortruncated cone;

FIG. 2 is a view in perspective of a coated abrasive frustum; and

FIG. 3 is a view in perspective showing the frustum in FIG. 2 beingseparated into two frustums of lesser vertical height.

DETAILED DESCRIPTION OF THE DRAWING AND PREFERRED EMBODIMENT Turning nowto the drawing, there is disclosed in FIG. 1 thereof coated abrasivematerial which has been cut, in a known manner, from sheet material orthe like, not shown, to provide an arcuate shape. The arcuate shapedcoated abrasive material, as shown, has two curved edges ll, 12connected together by means of straight edges 13, 14. A curved lineoffering less tear resistance than the abrasive material per se isprovided, in accordance with my invention, at some desired locationbetween and parallel with the curved edges.

As seen from examining the drawing, straight edges 13, 14 are inclinedat an angle inwardly toward one another, curved edge 1 1 being ofsomewhat lesser length than curved edge 12.

The length of the curved edges and their degree of curvature, as well asthe angle of taper of the straight lines will depend, of course, uponthe particular application for the coneshaped abrasive article, as wellas the arbor or drive member therefor. Merely by way of example, thearcuate shaped coated abrasive material 10 shown in FIG. 1 may be diecut from a larger abrasive sheet so that a straight edge 13, 14 of 4.03inches is provided while at the same time providing curved edges 11, 12having radii of curvature of 8% inches and 12 1 1/16 inches,respectively.

In preparation to forming the truncated cone abrasive tool 16, shown inFIG. 2, a rectangular area 17 is skived, according to usual techniques,to remove the abrasive grain and adhesive bond. A suitable adhesivecomposition, for example, a polyurethane, is then applied to the skivedsurface, which may extend, for example, about one-fourth inch from theedge, and ends 13, 14 are overlapped and joined together in formation ofabrasive tool 16 in a manner well known to those skilled in the coatedabrasive art. Thus, on completion of joining straight edges l3, 14together, a hollow, flexible conically shaped abrasive tool 16 isprovided having a flat, cut-off top or upper end 18 and a bottom 19.Abrasive grain 20 is indicated in the drawing to be on the outside ofthe conical shaped abrasive tool; however, in some instances it may bedesirable to form the abrasive tool so that the grain is on the innersurface of the hollow tool.

In some instances to provide better adhesion, it may be desirable toback rub or abrade the back surface of edge 14 in an area complementaryto the skived area. This is conventionally done in the splicing ofcoated abrasive material to remove back surface treatment materials and,it is believed, requires no further explanation herein.

Alternatively, it may be desirable at times to join the straight edgestogether by means of a butt splice rather than by overlapping. Thismethod of joining is also practiced conventionally in the coatedabrasive industry.

Tear line 15 is provided in the same operation in which the arcuatesection is die-cut from a larger sheet of coated abrasive material. Asseen from the drawing, in the preferred embodiment, tear line 15 isdefined by slits 21 cut in the abrasive material which alternate withportions 22 of abrasive material which have not been cut. The manner ofmaking such a tear line is deemed well known and cutting means can beprovided on the same die as that used for cutting out the arcuatesection. In this way both cutting operations can be accomplishedsimultaneously.

Slits 21 can be from about one-eighth inch to about threeeighth inch inlength and preferably extend only about threesixteenth one-fourth inchin length. The portion 22 of coated abrasive material between eachadjacent slit 21 should be about three-sixteenth inches in length. Thesedimensions, it will be found, will result in a tear line providingsatisfactory separation, should that be desired by the user, yetpreclude inadvertent or undesired separation in use or during handlingand storage.

As is believed obvious, more than one tear line can be provided in thearcuate section thus making it possible to provide, in one operation, amultiplicity of conical shaped abrasive articles of the same angle butof lesser vertical height.

Although not absolutely critical, it is highly desirable that slits 21be provided, as shown in FIG. 1, at and extending inwardly from eachedge 13, 14. Thus, when an overlapped joint is formed, as in thepreferred embodiment of my invention, tearing will not be renderedunduly difficult, if not nearly impossible, to perform.

In the practice of my invention, one selects an abrasive tool frominventory having the general configuration shown in FIG. 2. The tool canbe used as is, on a suitable mandrel, where the grinding application canaccommodate its vertical height. However, most advantageously, where atool of lesser height is needed, the abrasive tool can be separated, asshown in FIG. 3, at the appropriate pre-determined tear line to satisfythese requirements. The location of the tear line and the resultingvertical height of the conical abrasive tools formed in the separationare, of course, pre-determined by the various applications to which theabrasive tool will be put. Although, in FIG. 3, abrasive tool 16 isshown separated into only two tools 16' and 16" of lesser verticalheight, tool 16 can be separated into a greater multiple of abrasivetools, as beforementioned, where this is desired.

Having now fully disclosed my invention, it is to be understood that thescope of the invention is intended to be limited only by the disclosureas a whole, including the appended claims.

I claim:

1. An abrasive tool having the shape of a hollow truncated cone, saidcone comprising an arcuate shaped flexible abrasive material defined byfirst and second spaced apart curved edges of different lengthsconnected together by spaced apart straight edges, said straight edgesbeing joined together along their length whereby said first and secondcurved edges define a truncated cone having a top and a bottom, and atleast one tear line located between said top and bottom and paralleltherewith and extending around the entire periphery of the cone shapedarticle.

2. An abrasive tool in accordance with claim 1 in which said tear linecomprises slits in the abrasive material alternating with portions ofthe abrasive material which are not slit.

3. An abrasive tool in accordance with claim 2 in which said slits arefrom about three-sixteenth inches to about one-fourth inch in length.

4. An abrasive tool in accordance with claim 3 in which said portions ofabrasive material are each about one-sixteenth inch in length.

5. An abrasive tool in accordance with claim 1 in which said straightedges are so positioned that one edge overlaps the other.

6. An abrasive tool in accordance with claim 5 wherein each of theoverlapped edges contain a slit extending inwardly therefrom and theslit in one edge is so located that it matches with the slit in theother edge thereby making for easier separation at the overlapped joint.

7. An abrasive tool in accordance with claim 6 in which the abrasivematerial has abrasive grain on its outer surface.

I I i I II

1. An abrasive tool having the shape of a hollow truncated cone, saidcone comprising an arcuate shaped flexible abrasive material defined byfirst and second spaced apart curved edges of different lengthsconnected together by spaced apart straight edges, said straight edgesbeing joined together along their length whereby said first and secondcurved edges define a truncated cone having a top and a bottom, and atleast one tear line located between said top and bottom and paralleltherewith and extending around the entire periphery of the cone shapedarticle.
 2. An abrasive tool in accordance with claim 1 in which saidtear line comprises slits in the abrasive material alternating withportions of the abrasive material which are not slit.
 3. An abrasivetool in accordance with claim 2 in which said slits are from aboutthree-sixteenth inches to about one-fourth inch in length.
 4. Anabrasive tool in accordance with claim 3 in which said portions ofabrasive material are each about one-sixteenth inch in length.
 5. Anabrasive tool in accordance with claim 1 in which said straight edgesare so positioned that one edge overlaps the other.
 6. An abrasive toolin accordance with claim 5 wherein each of the overlapped edges containa slit extending inwardly therefrom and the slit in one edge is solocated that it matches with the slit in the other edge thereby makingfor easier separation at the overlapped joint.
 7. An abrasive tool inaccordance with claim 6 in which the abrasive material has abrasivegrain on its outer surface.